Lecture 7

Question 1

Fst

Answer 1

is a measure of genetic differentiation between subpopulations
- it compares genetic variation within and among populations

Question 2

what is Ht is Fst calculation

Answer 2

total heterozygosity (the expected heterozygosity if the entire population were randomly mating)
- find the mean of p and the mean of q and use 2pq to find Ht

Question 3

what is Hs in the Fst calculation

Answer 3

subpopulation heterozygosity (the average heterozygosity within subpopulations)
- average all the 2pq (Ht) values

Question 4

fitness

Answer 4

the reproductive success of an individual with a particular phenotype
- survival to reproductive age
- mating success
- fecundity

Question 5

relative fitness

Answer 5

• w: genotype with the highest absolute fitness
• wmax=1
  -fitness of all other genotypes standardized by dividing by wmax

Question 6

what are the 5 forces of change

Answer 6

1. mutation
2. nonrandom mating
3. gene flow
4. genetic drift
5. natural selection

Question 7

Why do allele frequencies vary in natural populations?

Answer 7

Local environmental conditions determine the direction of selection, especially when different fitness effects oppose each other.

Question 8

When does genetic drift have a stronger effect than selection?

Answer 8

In very small populations, random drift changes allele frequencies more than weak selection can.

Question 9

When does selection occur in a population?

Answer 9

Selection happens when genotypes differ in fitness, meaning some individuals have a higher chance of survival and reproduction.

Question 10

What two factors determine the outcome of selection?

Answer 10

1. Initial allele frequency
2. The allele’s effect on fitness (advantageous or disadvantageous).